Kim Stanley Robinson's Mars Trilogy

Unlike most sci-fi this is a gentle and warm book, sad to the point of elegiac in parts. the science is excellent but is definitely second fiddle to the characterization and the protrayal of the devlopment of an emerging society.

This was a great crowdsourced recommendation and I unhestiatingly recommend it to you. Whatever NASA finally announce in the next few weeks the best way I can think of to prepare for it is to read these books.